1. Field of the Invention
This invention relates to materials used in connection with a roof of a building structure and, more particularly, to a pitch pocket utilized to flash around protuberances which destroy the integrity of the roof, and the concomitant methodology for fabricating the pitch pocket.
2. Description of the Background Art
Due to the virtually limitless variety of architectural designs for buildings, there are very few standardized building dimensions, including the layout of each building's roof. Building elements such as vent pipes, anchors, and conduits penetrate the roof and, to avoid water leaks in the roof, it is required to flash the elements with a pitch pocket (or pan). A pitch pocket is essentially a mechanical device which rests on the roof and which is adapted to form a loose enclosure around each dement so as to retain flashing material such as roof tar in place during pouring and solidification. Older style pitch pockets were only manufactured in a few standard sizes. More recently, to ensure a waterproof enclosure and optimal use of flashing material, it has become the practice in the roofing industry to custom fabricate pitch pockets in a specialty sheet metal shop. Oftentimes, however, the pitch pockets are not properly sized due to inaccurate measurements or mis-communication about the measurements. Severe sizing problems ultimately lead to delays with a concomitant increase in the cost of installing or repairing roofs.
One type of conventional pitch pocket (including a custom one) is constructed using a number (e.g., 2 or 4) of separate metal pieces which are placed to encompass the protuberance, and then the individual pieceparts are joined together mechanically to form a composite pitch pocket which is typically anchored in place with nails or screws. A tool is usually used to form the pieceparts into a unitary pocket, requiring a degree of skill and dexterity. Also, hardware such as fasteners are often utilized to permanently join the pieceparts. Again, such detail-oriented procedures for forming the pocket are time consuming and therefore costly. Another problem area arises because the pieceparts are of a rigid, pre-formed shape to ensure that the pieceparts mate in a cooperative fashion. Representative of this conventional type of pitch pocket is U.S. Pat. No. 3,838,544 issued to Hindall. As disclosed by Hindall, four identical corner units are adapted for interfitting by forming each unit with two perpendicular, L-shaped walls and arranging one wall of a unit with a slot for accepting the grooved wall of another unit. However, such pre-formed shapes have the deleterious effect of making it difficult and costly for the roofer or supplier to inventory and store such a variety of sizes and shapes. In addition, a completed, square-shaped pitch pocket results in four seams (one in the middle of each side wall), each of which can become a potential weak point in the assembly. Finally, the pitch pocket of Hindall is time-consuming to fabricate because of the difficulty in forming the piecepart with a permanent right-angle bend.
Recently, as disclosed by U.S. Pat. No. 4,934,117, a circularly-shaped, plastic-type of pitch pocket has been devised with the intent of eliminating roof anchors. However, this pocket is manufactured as a unitary piece and the integrity of the pocket can only be maintained in new-type construction wherein the pocket can be slipped over the free-end of a protruding element such as a vent pipe. In pre-existing construction without access to a free end of an element, the plastic pocket must be cut and then spread apart to be placed around the element, thereby ruining the integrity of the unitary piece. Once cut, it is cumbersome to re-shape and maintain the pocket in place in order to maintain a water-tight seal. Moreover, the circularly shape piecepart is not conductive to storage because the pieceparts are bulky and not readily stackable.